Exhibit
      10.57

     

    EXECUTIVE
      EMPLOYMENT AGREEMENT

     

    BETWEEN:

     

    GRAN
      TIERRA ENERGY INC.,
      an
      Alberta corporation (“GTEI”)
      and
GRAN
      TIERRA ENERGY INC.,
      a
      Nevada corporation (“Gran
      Tierra”)

     

    (GTEI
      and
      Gran Tierra are collectively referred to herein as, the “Company”)
      

     

    -
      and


     

    DANA
      QUENTIN COFFIELD,
      an
      individual ordinarily resident in the City of Calgary  in
      the
      Province of Alberta 

     

    (the
      “Executive”)
      

     

    (collectively
      referred to as the “Parties”)

     

    RECITALS:

     

    
      	
              A.

            	
              The
                Executive has specialized knowledge and valuable skills and experience
                which are critical to the management and success of the
                business.

            


    

     

    
      	
              B.

            	
              The
                Company wishes to secure the services of the Executive and to ensure
                that
                the Executive remains President and Chief Executive Officer of the
                business.

            


    

     

    
      	
              C.

            	
              The
                Executive is currently an employee of the Company pursuant to an
                employment agreement between the Executive and the Company dated
                April 29,
                2005, as amended (the “Prior
                Agreement”).

            


    

     

    
      	
              D.

            	
              The
                Parties wish to set forth their entire understanding and agreement
                with
                respect to the subject matter hereof and replace the Prior Agreement
                in
                its entirety with this Executive Employment Agreement (the “Agreement”).

            


    

     

    THEREFORE,
      the
      Parties agree as follows:

     

    ARTICLE
      1

    DUTIES
      AND RESPONSIBILITIES

     

    1.1 Position. 

     

    The
      Company confirms the appointment of the Executive to the position of President
      and Chief Executive Officer. The Executive will undertake those duties and
      responsibilities set out in Schedule “A” to this Agreement as well as those
      duties reasonably assigned to the Executive by the Board of Directors of the
      Company (the “Board”).
      The
      Executive will report to the Board. The parties agree that the relationship
      between the Company and the Executive created by this Agreement is that of
      employer and employee.


    
      
        
        

      

      
        
        

        
          

        

      

      
        
        

      

    


    1.2 Other
      Engagements. 

     

    The
      Executive shall not engage in any other business, profession or occupation
      which
      would conflict with the performance of his duties and responsibilities under
      this Agreement, either directly or indirectly, including accepting appointments
      to the boards of other companies without the prior written consent of the
      Board.

     

    1.3 Reassignment. 

     

    The
      Company shall not reassign the Executive to another position within the Company
      itself, or to a position within a subsidiary, affiliated or related corporate
      entity (“Member
      Company”
or
      “Member
      Companies”)
      or
      alter the duties, responsibilities, title, or reporting lines of the Executive
      or change the location of the Executive’s employment unless the Executive agrees
      to such reassignment or alteration.

     

    1.4 Travel. 

     

    The
      Executive shall be employed at the Company’s location in Calgary, Alberta. The
      Executive shall be available for such business related travel as may be required
      for the purposes of carrying out the Executive’s duties and responsibilities.
      The Executive shall be entitled to business class tickets for domestic or
      international flights with a duration of more than 1 hour. The Executive will
      be
      entitled to choose suitable accommodations when travelling on Company
      business.

     

    ARTICLE
      2

    TERM
      OF EMPLOYMENT

     

    Executive’s
      employment with the Company is for no specified duration and constitutes at-will
      employment. Executive’s employment may be terminated at any time by either of
      the Parties, subject to the provisions of Article 9.

     

    ARTICLE
      3

    BASE
      SALARY

     

    The
      Executive will be paid an annual salary in
      an
      amount determined by the Board,
      subject
      to applicable statutory deductions (the “Base
      Salary”).
      The
      Executive’s Base Salary will be payable in accordance with Company practices and
      procedures as they may exist from time to time. Base Salary will be reviewed
      and
      may be increased on an annual basis by the Board, with input from the
      Executive.

     

    ARTICLE
      4

    BONUS

     

    4.1 Bonus
      Eligibility. 

     

    The
      Executive shall be eligible to receive an annual bonus payment in addition
      to
      Base Salary and other compensation for each year of the Executive’s employment
      (the “Bonus”)
      as
      determined by the Board from time to time.


    
      
        
        

      

      
        2.

        
          

        

      

      
        
        

      

    


    4.2 Bonus
      Payment. 

     

    The
      Bonus
      shall be payable within sixty (60) days of the end of the fiscal year, and
      will
      be based upon the Executive’s performance during the preceding
      year.

     

    ARTICLE
      5

    BENEFITS

     

    The
      Executive shall be entitled to participate in and to receive all rights and
      benefits under any life insurance, disability, medical, dental, health and
      accident plans maintained by the Company for its employees and for its executive
      officers specifically. The Company will continue to pay the Executive’s Base
      Salary in the event the Executive becomes disabled until such time as the
      Executive begins to receive long-term disability insurance
      benefits.

     

    ARTICLE
      6

    VACATION

     

    The
      Executive will be entitled to five weeks vacation per year. Payment of all
      vacation pay will be at Base Salary. The Executive will arrange vacation time
      to
      suit the essential business needs of the Company. Unused vacation entitlement
      will be carried over into the following calendar year to a maximum entitlement
      of eight weeks in any one year. On leaving the employment of the Company for
      whatever reason, the Company will compensate the Executive for any accrued
      but
      unused vacation entitlement based upon the Executive’s then current Base
      Salary.

     

    ARTICLE
      7

    STOCK
      OPTIONS

     

    The
      Company will provide the Executive with the right to participate in stock option
      plans and/or incentive award plans approved by the Board.

     

    ARTICLE
      8

    PERQUISITES
      AND EXPENSES

     

    The
      Company recognizes that the Executive will incur expenses in the performance
      of
      the Executive’s duties. The Company shall reimburse the Executive for any
      reasonable out of pocket expenses incurred in the course of
      employment.

     

    ARTICLE
      9

    TERMINATION
      OF EMPLOYMENT

     

    9.1 Termination
      Without Notice. 

     

    This
      Agreement and the Executive’s employment with the Company may be terminated,
      without the Company being obligated to provide the Executive with advance notice
      of termination or pay in lieu of such notice, whether under contract, statute,
      common law or otherwise, in the following circumstances:


    
      
        
        

      

      
        3.

        
          

        

      

      
        
        

      

    


    (a) Voluntary
      Resignation. 

     

    In
      the
      event the Executive voluntarily resigns, except where the Executive resigns
      for
      Good Reason as provided for in this Agreement, the Executive will give a minimum
      of ninety (90) days’ advance written notice to the Company. The Executive will
      not be entitled to receive any further compensation or benefits whatsoever
      other
      than those which have accrued up to the Executive’s last day of active service
      with the Company. The Company may, at its discretion, waive in whole or in
      part
      such notice with payment in lieu to the Executive;

     

    (b) Cause. 

     

    "Cause"
      is defined as any of the following: 

    


    (a)
      conviction of, or plea of nolo contendere to, a felony; 

    


    (b)
      participation in a fraud against the Company; 

    


    (c)
      participation in an act of dishonesty against the Company intended to result
      in
      your personal enrichment; 

    


    (d)
      willful material breach of the Company's written policies; 

    


    (e)
      intentional significant damage to the Company's property by you; 

    


    (f)
      material breach of this Agreement; or 

    


    (g)
      conduct by you that, in the good faith and reasonable determination of the
      Board, demonstrates gross unfitness to serve provided that in such event, the
      Company shall provide notice to you describing the nature of the gross unfitness
      and you shall thereafter have ten (10) days to cure such gross unfitness if
      such
      gross unfitness is capable of being cured. 

    


    The
      Company may not terminate your employment for Cause unless and until you receive
      a copy of a resolution duly adopted by the affirmative vote of at least a
      majority of the Board of Directors of the Company ("Board") finding that in
      the
      good faith opinion of the Board, that "Cause" exists and specifying the
      particulars thereof in reasonable detail. 

    


    9.2 Termination
      by the Company without Cause.

     

    The
      Company may terminate the Executive’s employment without Cause at any time by
      providing the Executive with a separation package (the “Separation
      Package”)
      equal
      to two years’ Total Cash Compensation.


    
      
        
        

      

      
        4.

        
          

        

      

      
        
        

      

    


    “Total
      Cash Compensation” is defined as the annualized amount of Base Salary plus Bonus
      Payment for the prior 12-month period.

     

    The
      Separation Package shall be payable in a lump sum within thirty (30) days of
      termination.

     

    9.3 Termination
      by the Executive for Good Reason. 

    


    Should
      the Executive terminate his employment for Good Reason, as hereinafter defined,
      he shall receive the Separation Package set out in section 9.2. Failure of
      the
      Executive to terminate his employment on the occurrence of any event which
      would
      constitute Good Reason shall not constitute waiver of his right under this
      section 9.3. Notwithstanding the foregoing, Executive may terminate his
      employment for Good Reason so long as Executive tenders his resignation to
      the
      Company within thirty (30) days after the occurrence of the event that forms
      the
      basis for the resignation for Good Reason; provided, however, that Executive
      must provide written notice to the Company describing the nature of the event
      that Executive believes forms the basis for the resignation for Good Reason,
      and
      the Company shall thereafter have ten (10) days to cure such event.


    


    “Good
      Reason” is defined as the occurrence of any of the following without the
      Executive’s express written consent:

    


    
      	
            	(a)	
              an
                adverse change in the Executive’s position, titles, duties (including any
                position or duties as a director of the Company) or responsibilities
                (including new, additional or changed formal or informal reporting
                responsibilities) or any failure to re-elect or re-appoint him to
                any such
                positions, titles, duties or offices, except in connection with the
                termination of his employment for
                Cause;

            


    

    


    
      	
            	(b)	
              a
                reduction by the Company of the Executive’s Base Salary except to the
                extent that the annual base salaries of all other executive officers
                of
                the Company are similarly reduced or any change in the basis upon
                which
                the Executive’s annual compensation is determined or paid if the change is
                or will be adverse to the Executive except that an award of annual
                performance bonuses by the Company’s Compensation Committee (and approved
                by the Board of Directors) are discretionary and in no instance shall
                be
                considered adverse to Executive if such performance bonus is reduced
                from
                a prior year or if an annual performance bonus is not
                paid;

            


    

    


    
      	
            	(c)	
              a
                Change in Control (as defined below) of the Company occurs;
                or

            


    

    


    
      	
            	(d)	
              any
                breach by the Company of any material provision of this
                Agreement.

            


    

    


    A
“Change
      in Control” is defined as: 

     

    (a)
      a
      dissolution, liquidation or sale of all or substantially all of the assets
      of
      the Company;

     

    (b)
      a
      merger or consolidation in which the Company is not the surviving
      corporation;


    
      
        
        

      

      
        5.

        
          

        

      

      
        
        

      

    


    (c)
      a
      reverse merger in which the Company is the surviving corporation but the shares
      of the Company’s common stock outstanding immediately preceding the merger are
      converted by virtue of the merger into other property, whether in the form
      of
      securities, cash or otherwise; or 

    


    (d)
      the
      acquisition by any person, entity or group within the meaning of Section 13(d)
      or 14(d) of the Exchange Act, or any comparable successor provisions (excluding
      any employee benefit plan, or related trust, sponsored or maintained by the
      Company or any affiliate of the Company) of the beneficial ownership (within
      the
      meaning of Rule 13d-3 promulgated under the Exchange Act, or comparable
      successor rule) of securities of the Company representing at least fifty percent
      (50%) of the combined voting power entitled to vote in the election of
      directors.

    


    ARTICLE
      10

    DIRECTORS/OFFICERS
      LIABILITY

     

    10.1 Indemnity.

     

    Gran
      Tierra shall provide to the Executive indemnification in accordance with the
      Indemnification Agreement entered into between Gran Tierra and the
      Executive.

     

    10.2 Insurance.

     

    
      	 	
              (a)

            	
              Gran
                Tierra shall purchase and maintain, throughout the period during
                which the
                Executive acts as a director or officer of Gran Tierra or a Member
                Company
                and for a period of two years after the date that the Executive ceases
                to
                act as a director or officer of Gran Tierra or a Member Company,
                directors’ and officers’ liability insurance for the benefit of the
                Executive and the Executive’s heirs, executors, administrators and other
                legal representatives, such that the Executives insurance coverage
                is, at
                all times, at least equal to or better than any insurance coverage
                Gran
                Tierra purchases and maintains for the benefit of its then current
                directors and officers, from time to
                time.

            


    

     

    
      	 	
              (b)

            	
              If
                for any reason whatsoever, any directors’ and officers’ liability insurer
                asserts that the Executive or the Executive’s heirs, executors,
                administrators or other legal representatives are subject to a deductible
                under any existing or future directors’ and officers’ liability insurance
                purchased and maintained by Gran Tierra for the benefit of the Executive
                and the Executive’s heirs, executors, administrators and other legal
                representatives, Gran Tierra shall pay the deductible for and on
                behalf of
                the Executive or the Executive’s heirs, executors, administrators or other
                legal representatives, as the case may
                be.

            


    

     

    
      
        
        

      

      
        6.

        
          

        

      

      
        
        

      

    


    10.3 Survival. 

     

    The
      provisions of sections 10.1 and 10.2 of this Agreement shall survive the
      termination of this Agreement or the employment of the Executive with the
      Company and such provisions shall continue in full force and effect in
      accordance with such Indemnification Agreement and the provisions of this
      Agreement for the benefit of the Executive.

     

    ARTICLE
      11

    NON-COMPETITION
      AND CONFIDENTIALITY

     

    11.1 Non-Competition. 

     

    The
      Executive recognizes and understands that in performing the duties and
      responsibilities of his employment as outlined in this Agreement, he will be
      a
      key employee of the Company and will occupy a position of high fiduciary trust
      and confidence, pursuant to which he has developed and will develop and acquire
      wide experience and knowledge with respect to all aspects of the services and
      businesses carried on by Gran Tierra and its Member Companies and the manner
      in
      which such businesses are conducted. It is the expressed intent and agreement
      of
      the Executive and of the Company that such knowledge and experience shall be
      used solely and exclusively in the furtherance of the business interests of
      Gran
      Tierra and its Member Companies and not in any manner detrimental to them.
      The
      Executive therefore agrees that so long as he is employed by the Company
      pursuant to this Agreement he shall not engage in any practice or business
      in
      competition with the business of Gran Tierra or any of its Member
      Companies.

     

    11.2 Confidentiality. 

     

    The
      Executive further recognizes and understands that in the performance of his
      employment duties and responsibilities as outlined in this Agreement, he will
      be
      a key employee of the Company and will become knowledgeable, aware and possessed
      of all confidential and proprietary information, know-how, data, strategic
      studies, techniques, knowledge and other confidential information of every
      kind
      or character relating to or connected with the business or corporate affairs
      and
      operations of Gran Tierra and its Member Companies and includes, without
      limitation, geophysical studies and data, market data, engineering information,
      shareholder data, client lists, compensation rates and methods and personnel
      information (collectively “Confidential
      Information”)
      concerning the business of Gran Tierra and its Member Companies. The Executive
      therefore agrees that, except with the consent of the Board, he will not
      disclose such Confidential Information to any unauthorized persons so long
      as he
      is employed by the Company pursuant to this Agreement and for a period of 24
      months thereafter; provided that the foregoing shall not apply to any
      Confidential Information which is or becomes known to the public or to the
      competitors of Gran Tierra or its Member Companies other than by a breach of
      this Agreement.

     

    11.3 Following
      Termination of Agreement. 

     

    Subject
      to this provision and without otherwise restricting the fiduciary obligations
      imposed upon, or otherwise applicable to the Executive as a result of the
      Executive having been a senior officer and key employee of the Company, the
      Executive shall not be prohibited from obtaining employment with or otherwise
      forming or participating in a business competitive to the business of the
      Company after termination of this Agreement and the Executive’s employment with
      the Company.


    
      
        
        

      

      
        7.

        
          

        

      

      
        
        

      

    


    ARTICLE
      12

    CHANGES
      TO AGREEMENT

     

    Any
      modifications or amendments to this Agreement must be in writing and signed
      by
      all Parties or else they shall have no force and effect. Notwithstanding the
      foregoing, the Company may assign this agreement to Member Company, without
      the
      consent of the Executive.

     

    ARTICLE
      13

    ENUREMENT

     

    This
      Agreement shall enure to the benefit of and be binding upon the Parties and
      their respective successors and assigns, including without limitation, the
      Executive’s heirs, executors, administrators and personal
      representatives.

     

    ARTICLE
      14

    GOVERNING
      LAW

     

    This
      Agreement shall be construed in accordance with the laws of the Province of
      Alberta and the laws of Canada applicable therein.

     

    ARTICLE
      15

    NOTICES

     

    15.1 Notice
      to Executive. 

     

    Any
      notice required or permitted to be given to the Executive shall be deemed to
      have been received if delivered personally to the Executive or sent by courier
      to the Executive’s home address last known to the Company.

     

    15.2 Notice
      to Company. 

     

    Any
      notice required or permitted to be given to the Company shall be deemed to
      have
      been received if delivered personally to, sent by courier, or sent by facsimile
      to:

     

    Gran
      Tierra Energy Inc.300, 611-10th Avenue S.W.

    Calgary,
      Alberta, Canada T2R 0B2

    Fax:
      (403) 265-3242

    Attn:
      Chief Financial Officer


    
      
        
        

      

      
        8.

        
          

        

      

      
        
        

      

    


    ARTICLE
      16

    WITHHOLDING

     

    All
      payments made by the Company to the Executive or for the benefit of the
      Executive shall be less applicable withholdings and deductions.

     

    ARTICLE
      17

    INDEPENDENT
      LEGAL ADVICE

     

    The
      Executive acknowledges that the Executive has been advised to obtain independent
      legal advice with respect to entering into this Agreement, that he has obtained
      such independent legal advice or has expressly deemed not to seek such advice,
      and that the Executive is entering into this Agreement with full knowledge
      of
      the contents hereof of the Executive’s own free will and with full capacity and
      authority to do so.

     

    ARTICLE
      18

    REPLACEMENT
      OF PRIOR AGREEMENT

    


    The
      Parties acknowledge that the Prior Agreement is hereby replaced in its entirety
      by this Agreement. Pursuant to Article 12 of the Prior Agreement, this Agreement
      shall be effective, and the Prior Agreement shall be terminated, upon the
      execution of this Agreement by the Parties. Upon such execution, all provisions
      of the Prior Agreement are hereby superseded in their entirety and replaced
      herein and shall have no further force or effect.

     

    (remainder
      of page intentionally left blank)


    
      
        
        

      

      
        9.

        
          

        

      

      
        
        

      

    


    In
      Witness Whereof
      the
      Parties have executed this Agreement as of the date set forth below, with an
      effective date as of June 17, 2008.

     

    
      	
              GRAN
                TIERRA ENERGY INC.

            	 	
              GRAN
                TIERRA ENERGY INC.

            
	 	 	 	 	 
	
              By:

            	
              /s/
                Martin H. Eden

            	 	
              By:

            	
              /s/
                Martin H. Eden

            
	 	
              Name:
                Martin H. Eden

            	 	 	
              Name:
                Martin H. Eden

            
	 	
              Title:
                CFO

            	 	 	
              Title:
                CFO

            
	 	 	 	 	 
	
              Date:

            	
              June
                17, 2008

            	 	
              Date:

            	
              June
                17, 2008

            
	 	 	 	 	 
	
              SIGNED,
                SEALED DELIVERED

            	 	 	 
	
              In
                the presence of:

            	 	 	 
	 	 	 	 
	
              /s/
                Sonya Messner

            	 	
              /s/
                Dana Coffield

            
	
              Witness

            	 	
              Dana
                Quentin Coffield

            
	 	 	 
	 	 	
              Date:
                17 June 08

            


    


    
      
        
        

      

      
        10.

        
          

        

      

      
        
        

      

    


    SCHEDULE
      “A”

     

    Duties
      and Responsibilities for President

     

    
      	
              ·

            	
              President
                shall report directly to the Board of
                Directors.

            


    

     

    
      	
              ·

            	
              Strategic
                leadership – formulate and recommend strategies to the Board to maximize
                shareholder value and long-term success of the Company; implement
                capital
                and operating plans; identify principal risks to the Company’s business
                and take appropriate steps to manage these risks; keep the Board
                fully
                informed on all significant operational, financial and other matters
                relevant to the Company.

            


    

     

    
      	
              ·

            	
              Technical
                Leadership – ensure a rigorous and disciplined approach to technical work
                of the Company with regard to geology geophysics and related disciplines;
                encourage technical innovation, imagination and
                pragmatism.

            


    

     

    
      	
              ·

            	
              Financial
                Leadership – develop annual capital commitment and expenditure budgets for
                approval by the Board; develop annual operating forecasts; authorize
                the
                commitment of funds sanctioned by the Board; authorize the commitment
                of
                contracts, transactions and arrangements in the ordinary course of
                business; take reasonable steps to ensure the Company’s assets are
                adequately safeguarded.

            


    

     

    
      	
              ·

            	
              Administrative
                Leadership – develop and maintain a sound and effective organizational
                structure; ensure all members of the organization have clear
                responsibilities.

            


    

     

    
      	
              ·

            	
              Public
                Leadership – maintain effective communications and appropriate
                relationships with shareholders and other stakeholders; manage
                interactions between the Company and the public and act as the principal
                spokesperson for the Company.

            


    

     

    
      	
              ·

            	
              Compliance
                Leadership – establish effective control and coordination mechanisms for
                all operations arid activities of the Company; take reasonable steps
                to
                ensure the safe, efficient operation of the Company and its
                employees/workers ; ensure all operations and activities are in compliance
                with laws, regulations and the Company’s code of business conduct and
                ethics and other policies and practices approved by the Board; foster
                a
                high performance corporate culture that promotes ethical practices
                and
                encourages individual and corporate integrity and
                responsibility.